Frequency multiplication



April 30,1935 B. SALZBERG 1,999,884

FREQUENCY MULTIPLICATI ON Filed Dec; 26, 1930 INVENTOR BERNARD SALLBERG 'ATTOR-NEY Patented Apr. 30, 1935 UNITED STATES FREQUENCY MULTIPLIOATION Bernard 'Salzberg, Rocky Point, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Application December 26, "1930, Serial No. 504,733

2; Claims.

This invention appertains to, in general, the multiplication of the frequency of alternating currents.

In order to extend the upper frequency limit of devices generating ultra short wave length electrical energy, it is an object of the present invention to provide a method and means for multiplying the frequency of the ultra short wave length energy, thereby providing a source of continuous wave oscillations in that portion of the frequency spectrum which has been hitherto accessible only by damped wave oscillators. It is to be clearly understood, however, that'although the present invention has special reference to extremely high frequency oscillations, the principles thereof are not limited thereto, but may be applied with equal force and effect to oscillations at relatively lower frequencies.

It is a further object of the present invention to provide a method and means for deflecting, that is, either rotating or bending an electron stream at a base or fundamental frequency and utilizing the deflected stream for producing oscillations of a frequency equal to or greater than that of the cyclic deflection.

Still a further object of the present invention is to provide a method and means for electrostatically deflecting an electron stream and utilizing the deflected stream to cyclically shock excite a circuit such that oscillations are built up therein at a frequency equal to or greater than the cyclic deflection of the stream. Still another object of the present invention is toprovide for the modulation and transmission of frequency multiplied energy derived in accordance with the present invention.

The invention is described more fully hereinafter with the aid of the accompanying drawing. given solely by way of illustration,- wherein,

Figure 1 illustrates schematically an arrangement for moving an electron stream cyclically in a closed curve, the moving stream being utilized to shock excite, at a frequency higher than the cyclic movement of the stream, a tuned high frequency circuit, and

Figure 2 illustrates an arrangement similar to Figure 1 wherein the stream is moved linearly in a single plane.

Referring to Figure 1, there is mounted, within an evacuated container 2, a cathode 4 suitably energized by means of a transformer 6, although, if desired, cathode heating may be accomplished by direct current. Electrons emanating from cathode 4 are compressed or concentrated into a narrow stream by a negatively charged cylindrical screen or grid-like structure 8 through which they are attracted by the positive potential applied to a cylindrical anode l0 polarizedby a source of potential [2? Resistors l4, iii are placed in the anode and screen leads respectively to provide high impedances, for preventing short circuits,

and to'automatically derive a source of bias for I I the grid.

Normally, the electron stream would be pulled through the anode It to the center point of annular insulator or element l8; but, by the action of deflector plates or electrodes, 22 and 24, 26, situated orthogonally about the stream, as shown, the stream is caused to rotate, in a manner more fully described hereinafter, so that itimpinges on insulator element I8 in a circular path indicated by dotted line 28.

Mounted on element 18 are a plurality of conducting members or targets 30 which, as shown, are alternately connected together and to conductors 32, 34' which in turn are connected to a balanced high frequency circuit 36 having movable U-shaped slides 38 therein for varying the tuning thereof.

Accordingly, it should be clear that as the stream passes or impinges upon successive conductor members 30, tuned circuit 36 will be impulse-excited at a frequency equal to the frequency of rotation of the stream multiplied by a whole number, that is, the number of contacts on element Hi. In other words, the tuning of circuit 36 should be adjusted to resonate at a frequency equal to half the number of contacts times the frequency of rotation of the electron stream.

Energy appearing in the tuned circuit '36 may be fed to a suitable transmission line 40 and radiated or transmitted over a suitable radiating antenna 42.

For modulation purposes, modulating potentials may be introduced, through the action of transformer 46, into conductor 44 maintaining contact members 30 at'a positive potential. It is to be understood, however, that modulation transformer 46 may be inserted with equal effect for causing modulating of the oscillations in tuned circuit 36 in either the anode or screen conductors 48, 50 respectively, or in the anode conductor or intermediate electrode conductor of ultra short wave length oscillator 54 of the type wherein V e-=E cos w t from an oscillator such as oscillator 54, is applied to the pair of electrodes 24, 26, the electron stream will be acted upon by a force proportional to the voltage between the electrodes such as e20, 22=E2o, 22 CO8 (wt+0) By adjusting the auxiliary line such that the potential wave applied toelectrodes 20, 22, experiences a phase change where t1 is the time required for the electrons to travel between the two pairs of electrodes 24, 26, and 20, 22, the electron stream will be acted upon by a resultant force made up of two perpendicular forces. The resultant force is given by the expression provided that the voltage amplitudes, E24-26 and Ezo-zz, are made equal.

The lengths of the branch circuits 60, 62 and the positions of the feeders 64, 66, 68, are adjusted so that the required equal voltages are obtained between the plates 20, 22 and 21, 26; and so that no standing waves exist along the phasing line 55 and the line from the oscillator.

Consequently, the electron stream will rotate about a circle or a closed curve whose radius is proportional to kE, with an angular velocity w.

Adjustment for the time of travel of electrons between the pairs of plates may be eliminated by arranging the electrodes 20, 22, and 24, 26, at the same point on the longitudinal axis of the stream in which case the time h becomes zero and 0 then becomes equal to If it is desired to multiply the frequency 11. times it is necessary to provide 2n contacts connected as shown to the balanced tuning system 36. The

or degrees.

leads to the tuning system should be symmetrical,

Accordingly, it should be clear that the circuit 36 will be shock excited at the rate'of 2n alternate, positive and negative pulses per second, and, as it is tuned, the large voltages and currents peculiar to the resonant condition will be built up therein. If the contacts be only two in number the device will function as an amplifier, operating at the base frequency.

It is not necessary that the electron stream be caused to pursue a circular path to accomplish frequency multiplication. By proper adjustment of the voltages between the two pairs of control plates, the path may be arranged in the form of an ellipse; and by proper arrangement of the phase and voltage differences between the two sets of control plates, a variety of other paths may be obtained. In all cases, the contacts, or targets, should be located along the path so that the impulses occur at equal time intervals.

In Figure 2, frequency multiplication is accom plished by the linear deflection of an electron stream. This method may be regarded as a limiting case of Figure 1, where the voltage between one set of plates is reduced to zero, so that the circle degenerates into a line.

oscillatory energy from source 10 applied to electrodes 12, 14, cause electron stream 16 to move back and forth over a row of conducting members or contacts 18 mounted on an insulating element 8!) and alternately connected to conductors 82.

As a result of the rapid movement of the stream over the conducting members, circuit 36 of Figure 2 will be shock excited at a frequency equal to the frequency of source 10 multiplied by a whole number, bearing a definite relation to the number of contacts, 18, used. If it is desired to multiply the frequency 11. times, it is necessary to provide (n+1) contacts, or targets.

As the stream, in general, will move back and forth over the contacts at varying speeds, the spacing of the contacts or conducting members should be so chosen that the stream during its motion will cause shock excitation at equal time intervals. In the case of a harmonic applied voltage, the spacing is given by the projection of the corresponding circular arrangement on a straight line.

The extent of the motion of the stream may be varied by suitably adjusting the amplitude of the exciting voltage.

Having thus described my invention, what I claim is:

1. In an electrical system utilizing alternating electric currents, an electron discharge device having a cathode, means for causing a stream of electrons to emanate from said cathode, a circular element having a plurality of conductive members thereon which serve as targets in the path of said stream, alternate conductive members on said element being connected together; a plurality of pairs of electrodes located about said stream of electrons, said pairs of electrodes being spaced with respect to each other along the path of said stream, a circuit for applying alternating current voltages to one pair of said electrodes, a branch circuit connected with said first named circuit and with another pair of said electrodes, said branch circuit including conductors, the length of which may be varied to determine the phase relation of the voltages applied to said first and second pairs of electrodes, said alternating current potentials serving to rotate the electron stream cyclically past said conductive members, and, a high frequency circuit connected to thealternately connected members whereby movement of said stream past said members causes shock excitation of said high frequency circuit.

2. In an electrical system utilizing alternating electric currents, an electron discharge device having a cathode, means for causing a stream of electrons to emanate from said cathode, a circular element, having a plurality of conductive members thereon, in the path of said stream, alternate conductive members on said element being connected together, means for electrostatically rotating the electron stream cyclically past said conductive members, a high frequency circuit comprising linear conductors including tuning means connected to the alternately connected members whereby movement of said stream past said members causes shockexcitation of said high frequency circuit, a source of modulating potentials connecting a symmetrical point on said high frequency circuit to ground, and a work circuit capacitively coupled to said high frequency circuit.

3. Ultra high frequency oscillation producing means comprising, a thermionic tube having an electron stream producing element, and a target comprising, a plurality of conducting members spaced about the path of said stream remote from the stream producing element, alternating ones of said conducting members being conductively connected together, a plurality of pairs of deflecting plates in said tube, pairs of said plates being located on opposite sides of said A stream and spaced along the path of said stream relative to each other, linear conductors for applying alternating current potentials to the plates of one of said pairs of plates, other linear conductors connecting said first named conductors to a second pair of plates, said other linear conductors including means for shifting the phase of the potentials applied ,to said last pair of plates by 90 with respect to the phase of the potentials applied to said first named pair of plates, and an oscillation circuit comprising linear conductors connected to said conducting members in said target, said linear conductors including means to tune said circuit to a frequency which is a multiple of the frequency of the alternating current potential applied to the deflecting plates.

4. Means for multiplying the oscillations from a high frequency oscillation source to produce ultra high frequency oscillations comprising, a

ment, and pairs of deflecting plates spaced alongthe path of said stream between said source and said target, a linear circuit for applying alternating current potentials from said source to the pair of deflecting plates nearest to said electron stream producing element, a circuit including linear conductors connecting said first named circuit to another pair of said deflecting plates, said last named circuit including phase shifting means, a circuit comprising linearconductors connected together and to groups of conducting elements in said target, and means in said linear conductors for tuning said circuit to a frequency which is a multiple of the frequency applied to said deflecting plates.

5. Ultra high frequency oscillation producing means comprising, a thermionic tube having an electron stream producing element, and a target comprising, a plurality of conducting members arranged adjacent the normal path of said stream'and remote from the stream producing element, a plurality of pairs of deflecting plates in said tube, pairs of said plates being located on opposite sides of said stream and spaced along said stream relative to each other, linear conductors for applying alternating current potentials tosaid plates, said linear conductors including means for shifting the phase of the potentials applied to certain of said pairs of plates,

ments connected to the conducting members in said target, said linear elements including means to tune the same.

6. Means for multiplying the oscillations from a high frequency oscillation source to produce ultra high frequency oscillations comprising, a thermionic tube of the cathode ray type, said tube having an electron stream producing element, a target comprising a plurality of conducting elements located adjacent the normal path of said stream and remote from the stream producing element, and deflecting plates spaced along the path of said stream between said source and said target, a circuit including linear conductorsfor applying alternating current potentials to a deflecting plate, a circuit including linear conductors connecting said first named circuit to another of said deflecting plates, said last named circuit including phase shifting means, whereby said electron stream is rotated, a circuit comprising linear conductors connected together and to groups of conducting elements in said target, and means in said linear conductors for tuning said circuit to a-frequency greater than the frequency of said first mentioned oscillation source.

7. Ultra frequency signalling means comprisn ra thermionic tube having an electron stream producing element, and a target comprising, a plurality of conducting members spaced about the path of said stream remote from the stream producing element, alternating ones of said conducting members being conductively connected together, a plurality of pairs of deflecting plates in said tube, pairs of said plates being located on opposite sides of said stream and spaced along the path of said stream relative to each other, linear conductors for applying alternating current potentials to said plates, said linear conductors including means for shifting the phase of the potentials appliedto certain of said pairs of plates by 90, an oscillation circuit comprising linear conductors connected to said conducting members in said target, said linear conductors including means to tune said circuit" to a frequency which is a multiple of the frequency applied to the deflecting plates, and means for modulating at signal frequency the oscillations produced comprising a circuit for applying modulating potentials to the electrical center of the linear conductors in said oscillation circuit.

8. The combination of a high frequency oscillation generator of the thermionic type and an oscillation circuit coupled thereto, a cathode ray tube having a plurality of pairs of deflecting plates, a circuit for connecting each plate of one pair of said plates to different points on said oscillation circuit, linear conductors of variable length connecting each of the plates of said one pair of plates to a plate of another of said pairs of plates, said cathode ray tube having an electron stream source and N pairs of targets, an oscillation circuit connected to said pairs of targets, said oscillation circuit comprising linear conductors of variable length which tune said circuit to resonance at a selected ultra high frequency N where f is the frequency of the oscillations generated by said high frequency generator, a load circuit connected with said oscillation circuit, and modulating means connected with said oscillation circuit.

BERNARD sALzBEao. 

